JP2624122B2 - Lubricant composition for hot rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention exerts an excellent lubricating effect in hot rolling such as steel sheet rolling, section steel rolling, wire rod rolling, and hole rolling such as pipe making of various steel materials including carbon steel and stainless steel. , A hot working lubricant composition. The lubricant composition of the present invention is particularly effective for preventing seizure and reducing abrasion during hot rolling of a steel material such as a stainless steel material where seizure easily occurs, and for preventing scale flaws during hot rolling of a carbon steel material.

[0002]

2. Description of the Related Art During hot rolling of various steel materials, if the material to be rolled is baked on a rolling roll, various surface roughness occurs on the surface of the rolling roll, which is printed on the surface of the steel material and becomes a surface flaw. The surface of the steel material having the surface flaws is repaired by a polishing operation, but it involves an increase in man-hours for the maintenance, and scraps having severe flaws have to be scrapped, which causes an increase in cost.

[0003] Defects on the surface of a steel material caused by seizure are a serious problem particularly in hot rolling of a stainless steel material. Stainless steel generally has a chemical composition containing 13% or more Cr by weight, forms a stable chromium oxide protective film on the surface of steel, and provides excellent corrosion resistance and oxidation resistance by passivating the surface. Demonstrate. However, this surface oxide film is significantly thinner than that of carbon steel, and has high hot deformation resistance. Therefore, stainless steel material is likely to cause metal-to-metal contact with the rolling roll during hot rolling,
As a result, seizure occurs, causing roll surface roughness and steel material surface flaws.

[0004] As described above, the stainless steel material is liable to seize and, in addition, a stainless steel product generally used without painting requires a particularly beautiful surface skin. This is particularly problematic in hot rolling of steel.

[0005] However, the problem of seizure is not limited to hot rolling of stainless steel, but may also occur in hot rolling of carbon steel or special steel. That is, while high productivity, high quality, and low cost have been pursued in recent years, high-speed, high-pressure rolling has been performed more than ever. For this reason, the rolling load increases, and seizure is likely to occur during hot rolling.

[0006] Recently, with the development of schedule-free rolling, new hot rolling mills, and new wear-resistant rolls typified by high-carbon high-speed steel rolls, seizure prevention has become an even more important issue. Has become.

In addition, during hot rolling of carbon steel material, in addition to seizure, scale flaws are formed, in which oxide scale remaining on the surface of the steel material is pushed in by rolling to form scale flaws, thereby deteriorating product quality. Has also caused problems.

As measures against seizure, use of lubricants such as hot rolling oil, optimization of roll cooling, and review of rolling operation conditions have been conventionally performed. In particular, it is possible to supply a lubricant to the rolling roll or its reinforcing roll for the purpose of reducing the frictional force between the rolling roll and the steel to be rolled, preventing the roughening of the roll and reducing the wear, thereby improving the quality of the rolled product. Has been considered effective.

As a lubricant used for hot rolling of carbon steel, Japanese Patent Application Laid-Open No. 47-19807 discloses that a small amount (0.1 to 10% by weight of the whole) of a water-replacement agent is added to a natural fatty acid oil, A lubricant composition containing a mineral lubricating oil has been proposed. Oil-soluble sulfonates as water displacing agents
(Eg, metal salts of petroleum sulfonic acid) have been used. Further, lubricants in which finely divided calcium carbonate of about 10 μm is dispersed in water or a lubricating base oil are described in JP-B-62-14598, JP-B-62-39198, and JP-B-62-39199. I have.

[0010] However, although these lubricants have an effect of slightly lowering the coefficient of friction, the present situation is that a sufficient seizure prevention effect and scale flaw prevention effect are not obtained.

These lubricants are intended to lubricate carbon steel materials during hot working and rolling. When used in hot rolling of stainless steel materials, the material to be rolled is severely seized on the surface of a rolling work roll. In addition, there is a problem that the rolling efficiency is extremely reduced, and thus it cannot be used for hot rolling of stainless steel.

As a lubricant for hot rolling of stainless steel, a lubricant in which iron oxide powder is dispersed in lubricating oil is disclosed in JP-A-63-254195, and graphite is disclosed in JP-A-1-167396. A dispersion of powder in a viscous aqueous solution has been proposed.

However, even if the oxidized powder is dispersed in order to suppress the direct contact state between the metal of the rolling roll and the material to be rolled, the effect of sufficiently preventing seizure on the roll and roll wear can be obtained. Not. In addition, graphite has an extremely low coefficient of friction, which causes poor engagement of the material to be rolled at the start of rolling and causes slip during rolling.Therefore, it is sufficient to exhibit seizure preventing effect and friction reducing effect. It cannot contain graphite in an appropriate amount.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to prevent seizure of a material to be rolled on a rolling roll surface and to significantly reduce roll wear in hot rolling of various steel materials including stainless steel. In addition, it is possible to prevent the occurrence of scale flaws on the surface of the steel material in the hot rolling process of the carbon steel material, thereby improving the quality of the rolled product and the working efficiency. To provide things.

[0015]

Means for Solving the Problems The present inventors have previously found that a lubricant composition for hot rolling in which a highly basic metal salt sulfonate is contained in a lubricating base oil can achieve the above object, A patent application was filed (Japanese Patent Application No. 4-276249). According to subsequent research, the highly basic metal salt phenate, like the highly basic metal salt sulfonate, is effective in preventing seizure of the steel material on the rolling roll and reducing roll wear,
It has been found that the effect of preventing scale flaws generated on the surface of steel material is high, and the highly basic metal salt phenate alone or as a mixture of the metal salt sulfonate and the lubricant contained in the lubricating base oil It has been found that the composition is also optimal for achieving the above object.

Therefore, the gist of the present invention is to provide a base number of 40 mg-
A metal salt phenate of KOH / g or more, or a mixture of the metal salt phenate and a metal salt sulfonate of base number 40 mg-KOH / g or more, in an amount of 20 to 70% by weight based on the total weight of the composition
In a lubricating base oil in a lubricant composition for hot rolling.

When a small amount of a phosphonate is added to the lubricant composition, the lubricating effect is further enhanced. Thus, in a preferred embodiment, the composition further comprises a phosphonate in an amount of up to 5% by weight, based on the total weight of the composition.

The metal salt phenate used in the present invention has a high basicity, that is, a base number of 40 mg-KOH / g or more. In addition, the metal salt sulfonate which may be used as a mixture with the metal salt phenate in the present invention is also similarly basified 40 mg-
It is highly basic with KOH / g or higher.

The base numbers of the metal salt phenate and the metal salt sulfonate can be measured by a potentiometric titration method specified in JIS K2501. The metal salt phenate used is 1
If it is a kind, its base number must be 40 mg-KOH / g or more. When two or more metal salt phenates are used, the weighted average of the base numbers of these metal salts (the average value in consideration of the respective amounts, hereinafter simply referred to as the average value) is 40 mg-KOH / g Anything above is good. That is, in this case, by using together with a high base number,
Those with a base number of less than 40 mg-KOH / g can be mixed. The same applies when two or more metal salt sulfonates are used.

For both the overbased metal salt phenate and the overbased metal salt sulfonate, alkaline earth metal salts (eg, Ca, Mg, Ba salts) are preferred, but other metal salts such as alkali metal salts are also preferred. Can be used.

These highly basic metal salt phenates and highly basic metal salt sulfonates have both been developed as detergents and dispersants for lubricating oils, and are incorporated in small amounts into engine oils, gear oils, industrial lubricating oils and the like. Is one of the lubricating oil additives to be used. However, there has been no attempt to use these highly basic metal salts themselves as the main lubricant in a lubricant composition.

[0022]

The overbased metal salt phenate is a metal salt of a long-chain alkylphenol derivative (sulfurized alkylphenol), and the alkylphenol derivative is dissolved in the presence of an alcohol, ketone, or polyoxyl alcohol in a solution in excess of a metal salt (eg, (Carbonates, oxides, hydroxides, etc.). The resulting overbased metal salt phenate contains an excess of fine metal salt, which is present as a colloidal dispersion in the oil.

On the other hand, a highly basic metal salt sulfonate is obtained by neutralizing a lipophilic petroleum sulfonic acid obtained by sulfonating an alkyl aromatic with fuming sulfuric acid or SO ₃ gas with a metal compound to form a metal salt, Metal carbonate or hydroxide in the presence of carbon dioxide, etc. [e.g., CaO or Ca (OH)
₂ ]. Like the overbased metal salt phenate, the overbased metal salt sulfonate also contains a metal salt ₃ to 15 times in excess of the normal salt, mainly in the form of carbonate (eg, CaCO ₃ ). Excess metal salt is dispersed in the oil as a colloidal dispersion.

Since these highly basic metal salt phenates and highly basic metal salt sulfonates have excellent heat resistance, they do not completely burn or decompose even during hot rolling, and are in a fluid or a state close to a fluid. It has been found that by contributing to lubrication, excellent lubricity as a lubricating agent is exhibited. In addition, since it has reactivity and adsorbability to metals and oxides on the steel surface, forming a lubricating reaction film on the surface reduces the direct contact between metals at the friction interface (between the roll and steel). It can suppress seizure and exhibit the effect of preventing seizure and reducing wear.

Excess metal salts, typically carbonates (eg, CaCO ₃ ), contained in highly basic metal salt phenates and metal salt sulfonates are produced in the process of producing highly basic metal salt sulfonates and metal salt phenates. Fine particles having a particle size of usually 150 μm or less, which spontaneously precipitate from the liquid, and form a colloidal dispersion in oil. When the metal salt is a carbonate, the carbonate is partially oxidized at a high temperature during hot rolling.
(For example, CaO, MgO, etc.).

Although these excessive metal salts and the fine particles of the metal oxide dissociated from the metal salts themselves have no lubricating effect, they have high lubricity against metals and oxides of highly basic metal salt phenates and metal salt sulfonates. It plays a role as a carrier that carries highly basic metal salt phenate and metal salt sulfonate to the friction interface in order to more easily exert the lubricating effect (particularly high chemical adsorption to oxides) by the adsorption action. At the same time, the metal salt fine particles uniformly transported to the friction interface between the roll and the steel material completely prevent direct contact between the rolling roll and the metal material and prevent seizure.

As described above, the highly basic metal salt phenate and metal salt sulfonate are formed by the lubricating effect of the metal salt phenate and the metal salt sulfonate itself and the precipitated metal salt fine particles forming a colloidal dispersion in oil. The synergistic effect with the carrier effect and the metal-to-metal contact inhibiting effect can remarkably exert the effect of improving seizure resistance and wear resistance to steel. This effect is observed when the particle size of the metal salt fine particles is 500 mm or less, and the effect is particularly remarkable when the particle size is 150 mm or less.

Therefore, a conventional powdery calcium carbonate having a particle size of about 1 to 10 μm, which is used in the prior art described in the above-mentioned Japanese Patent Publication No. Sho 62-14598, is dispersed in a lubricating base oil. The effect is clearly different from that of the lubricant. That is, in this conventional lubricant, it is said that the calcium carbonate powder itself exerts a lubricating effect.

Further, since the highly basic metal salt phenate and the highly basic metal salt sulfonate were originally developed as a detergent and dispersant, they have a strong dispersing and cleaning effect, and an oxide film remaining on the steel surface after rolling. Foreign substances such as (oxidized scale) and abrasion powder can be removed, and they are also effective in preventing scale flaws generated when they are pushed into the steel material surface.

By the above action, the lubricant composition of the present invention can prevent seizure on a rolling roll during hot rolling, greatly reduce roll abrasion, and reduce scale flaws. Can be prevented. as a result,
Good rolling product quality and high working efficiency can be ensured.

The lubricant composition of the present invention has a base number of 40 mg-
KOH / g or more metal salt phenate, or base number 40 mg-
A mixture of a metal salt phenate of KOH / g or more and a metal salt sulfonate of a base number of 40 mg-KOH / g or more is contained in an amount of 20 to 70% by weight based on the total weight of the composition. If the amount is less than 20% by weight, the lubricating effect of the metal salt phenate / metal salt sulfonate is insufficient, the roll abrasion increases, seizure cannot be sufficiently prevented, and scale flaws are difficult to prevent. On the other hand, when this amount exceeds 70% by weight, the viscosity of the lubricant composition increases, and it becomes difficult to supply the lubricant. A more preferable range of the amount of the highly basic metal salt phenate or the mixture of the metal salt phenate and the metal salt sulfonate is 30 to 60% by weight based on the total weight of the composition.

When the overbased metal salt phenate is used as a mixture with the overbased metal salt sulfonate, both of these components are almost as effective as the lubricant components. The ratio with the metal salt sulfonate is not particularly limited. That is, the content of the highly basic metal salt phenate in the case of a mixture can be varied within a wide range from about 1% (or less) to 70% by weight of the whole composition.

In the case of an alkaline earth metal salt, when the lubricating effect is compared with the same content and the same base number, the Ca salt is higher in both the metal salt phenate and the metal salt sulfonate than in the Ba salt, Mg and the like. Most effective. Therefore, in the case of a steel material such as stainless steel in which seizure easily occurs, or when the rolling load is particularly severe, it is preferable to select a Ca salt as the metal salt.

As described above, the metal salt phenate and the metal salt sulfonate each have a base number of 40 mg-KOH / g or more. If the base number is less than 40 mg-KOH / g, the lubricating effect required for a hot rolling lubricant cannot be achieved. The lubricating effect is improved as the base number is increased. Particularly, those having a base number of 200 mg-KOH / g or more are excellent in seizure prevention ability and abrasion resistance. Preferred base value of metal salt phenate and metal salt sulfonate is 200-500 mg-KOH
/ g range.

When the base number is less than 200 mg-KOH / g, a metal salt (eg, carbonate) as a carrier for improving the introduction of the metal salt phenate or metal salt sulfonate into the friction interface
And the amount of metal salt phenate or metal salt sulfonate introduced into the friction interface is reduced, so that the effect of reducing roll wear and preventing seizure may be insufficient.
However, even in the case of rolling stainless steel, if the degree of work is low, or if the workability is relatively good, the base number is low.
A highly basic metal salt phenate or a highly basic metal salt sulfonate of less than 200 mg-KOH / g can be effectively used.

On the other hand, highly basic metal salt phenates and metal salt sulfonates having a base number exceeding 500 mg-KOH / g are those having an appropriate function as a rolling lubricant, for example, those having viscosity and the like at the current state of the art. Since production is not possible, the upper limit of the preferred base number is set to 500 mg-KOH / g, but if the production technology allows, a base number exceeding 500 mg-KOH / g could be used.

As the highly basic metal salt sulfonate and the highly basic metal salt phenate, those having various base numbers are commercially available as detergents and dispersants, and commercially available products can also be used.

The particle size of the metal salt (mainly carbonate) does not significantly impair the effect of the present invention as long as it is 500 ° or less even when grown, but as mentioned above, it is most preferably 150 ° or less.

As a method for growing the carbonate grains, 150
方法 A method of using a highly basic metal salt sulfonate or metal salt phenate containing the following finely divided carbonate as a raw material and adding a polar substance such as water or methanol to promote crystal grain growth can be used.

The lubricant composition for hot rolling steel according to the present invention comprises a generally used lubricating base oil comprising a highly basic metal salt phenate alone or a highly basic metal salt phenate and a highly basic metal salt sulfonate. It is manufactured by mixing both. The amount of the metal salt phenate and the metal salt sulfonate is 20 to 70% by weight of the total composition as described above.
Range. Further, it is desirable to adjust the metal type, base number, and compounding amount of the overbased metal salt phenate and overbased metal salt sulfonate to be used according to the degree of lubrication performance required for the hot rolling to be applied. . For example,
In hot rolling of stainless steel in which seizure easily occurs, it is desirable to use a high basic Ca phenate and / or high basic Ca sulfonate having a base number of 200 mgKOH / g or more.

The adjustment of the base number of the highly basic metal salt phenate and the metal salt sulfonate is preferably carried out based on Ca sulfonate, Mg sulfonate, Ca phenate or Mg phenate, which can be obtained from products having particularly wide base numbers.

The lubricant composition of the present invention comprises 20 to 70% by weight of a highly basic metal salt phenate, or 20 to 70% by weight of a mixture of a highly basic metal salt phenate and a highly basic metal salt sulfonate, with the balance being A composition comprising only a lubricating base oil can be obtained, and such a composition is also sufficiently effective as a lubricant for hot rolling.

As the lubricating base oil, oils such as mineral oil, synthetic lubricating oil, rapeseed oil and lard oil, higher fatty acids and their esters, etc. can be used, and one type or a mixture of two or more types may be used. Commercially available hot rolling oil can be used as it is as the base oil.

If necessary, the lubricant composition of the present invention may comprise
Further, one or more other additives can be contained. Examples of additives that can be added to the lubricant composition of the present invention include phosphonates, solid lubricants, extreme pressure additives, antioxidants, pour point depressants, viscosity index improvers, and the like.

As the phosphonate (phosphonate), a trialkyl ester of phosphonic acid (eg, di-n
-Butylhexylphosphonate), acid phosphonate and the like. The incorporation of the phosphonate with the overbased metal salt phenate and / or the overbased metal salt sulfonate further enhances the lubricating effect, so that the phosphonate is added to the lubricant of the present invention in an amount of 5% by weight or less based on the total weight of the composition. It can be incorporated into the composition.

Examples of the solid lubricant include graphite, molybdenum disulfide, boron nitride, mica, talc and the like. Examples of extreme pressure additives include sulfur-based extreme pressure additives such as sulfurized fats and oils, sulfide mineral oil, and dinonyl polysulfide, and phosphoric acid-based extreme pressure additives such as tricresyl phosphate and dioctyl phosphate.

Examples of antioxidants include methylene-4,4
Bisphenols such as -bis (2,6-di-tert-butylphenol); alkylphenols such as di-tert-butylcresol; and naphthylamines. Examples of the pour point depressant and the viscosity index improver include polymethacrylate, polyolefin and the like.

The addition amount of the solid lubricant is about 1 to 10% by weight, the addition amount of the extreme pressure additive is about 1 to 15% by weight, the addition amount of the antioxidant is about 0.01 to 1.0% by weight, The amount of each of the point depressant and the viscosity index improver is 1 to 5% by weight.
It is about.

The lubricant composition of the present invention can be used not only for general stainless steel but also for high corrosion-resistant stainless steel having a Cr content of 20% by weight or more, which is used particularly for automobile exhaust gas materials.
(Eg, 20% Cr steel, 20% Cr-2% Mo steel, 20% Cr-5% Al steel, etc.), and high-load rolling such as low-temperature rolling and high-pressure rolling of carbon steel. The effect is remarkably exhibited.
Of course, even if it is used as a hot rolling lubricant at the time of normal rolling of a general steel material, the effect is remarkable. Further, the present invention is useful not only for sheet rolling, but also for hole rolling of shaped steel, wire rods and pipes.

According to the method for supplying the lubricant according to the present invention, there are provided an air atomizing method in which the lubricant is mixed with compressed air and supplied in the form of a spray, or a water which is mixed with water and supplied in accordance with the required viscosity and concentration. An injection method, a steam atomizing method or the like, which is supplied by atomizing with heated steam, is possible, and any of the methods can obtain the remarkable lubricating effect of the present invention. Needless to say, a method in which the lubricant composition is supplied as it is may be used, and in that case, the lubricant composition of the present invention may be dispersed in water with a dispersant to make it water-soluble, if necessary, to make it somewhat nonflammable. Other lubrication systems than those described above can also be used.

[0051]

Now, the present invention will be described in further detail with reference to specific examples.

Example 1 The lubricant compositions of Examples 1 to 4 of the present invention and Comparative Examples 1 and 2 shown in Table 1 were prepared by mixing the components with a homomixer. Table 1 shows the type of basic metal salt phenate used and its base number (average base number when two or more kinds are used). The blending was made such that the lubricating base oil was 60% by weight, and the remaining 40% by weight was a uniform ratio of metal salt phenate or a mixture of metal salt phenate and metal salt sulfonate. The commercial hot rolling oil used as the lubricating base oil was a mixed oil composed of mineral oil, rapeseed oil, and α-olefin polymerized oil.

[0053]

[Table 1]

Example 2 In the same manner as in Example 1, the average base number was 300 to 400 mg-KOH / g, and the content of the highly basic metal salt phenate was changed, and Comparative Examples 3 to 8 were used. -5, Examples 9-11 of the present invention to which phosphonate was added, and the lubricant compositions of Conventional Examples 1-2, which are known stainless steel rolling lubricants, were prepared. The composition is shown in Table 2.

[0055]

[Table 2]

Using the lubricant compositions prepared in Examples 1 and 2, the following hot rolling test was carried out.

(Test 1) In a hot steel sheet rolling mill line
JIS SUS 430 stainless steel and ordinary steel (0.08% C-1.0% Mn)
(1800 tons and 2500 tons respectively)
(mm thickness) At the time of rolling, high-carbon high-speed rolls for rolling of three 4-stage hot rolling mills before the finishing tandem mill (main component: 2.2% C-3.0% Cr-4.0% Mo-6.0% V-1.0 % W) using a water injection type lubricant supply device.
Each of the lubricant compositions shown in Table 2 and Table 2 was supplied, and the steel sheet surface properties (presence or absence of surface flaws) after the seizure of the rolling roll and the rolling pickling were examined by visual observation.

Further, in order to check the wear of the rolling roll after rolling, the maximum wear depth of the upper and lower rolling rolls of the finishing No. 2 stand was measured with a profile meter, and the average value was obtained. I did it. The results are shown in Table 3 (JIS SUS 430) and Table 4 (Carbon steel).

[0059]

[Table 3]

[0060]

[Table 4]

As can be seen from the results shown in Tables 3 and 4, in the case of the present invention, seizure of the rolling roll was almost prevented, and seizure flaws and scale flaws were found on the steel sheet surface. Did not. Further, the abrasion amount of the roll was significantly reduced as compared with the comparative example and the conventional example. Further, from Examples 5 to 8 of the present invention and Comparative Examples 3 to 5, it is clear that a lubricant containing 20 to 70% by weight (particularly 30 to 60% by weight) of a highly basic metal salt phenate exhibits a large lubricating effect. I understood.

Inventive Example 1 having a base number of 40 to 200 mg-KOH / g,
Examples 2 and 4 of the present invention having a base number of 200 to 500 mg-KOH / g
As can be seen from comparison with 11, base number 200-500 mg-KOH
/ g of a highly basic metal salt phenate showed a further excellent lubricating effect (abrasion resistance and seizure resistance). Further, as can be seen from a comparison between Inventive Example 3 and 9, 10 and 11, when 5% or less of the phosphonate was contained, the lubricating performance was further improved.

The lubricating composition of Example 4 of the present invention comprising a phenate mainly composed of Ba as a metal salt was slightly inferior in the effect of the present invention and slightly seized on the roll. The properties were not affected. That is, even in this case, it is understood that the lubricity is excellent as compared with the conventional lubricant. Conventional Examples 1 and 2 were not satisfactory in both seizure resistance and wear resistance.

When other rolling rolls such as high Cr cast iron rolls, high alloy grain cast iron rolls, and adamite rolls are used as the rolling rolls, high-carbon high-speed steel
It goes without saying that the same effect as when a (high speed) roll is used can be obtained.

(Test 2) Steel pipes (JIS SUS 304 stainless steel, carbon steel) in the mandrel mill line During hot rolling, the hole type rolls (sizer roll, mandrel mill roll, reducer roll, etc.) of all the rolling stands were When each of the lubricant compositions shown in Tables 1 and 2 was supplied as it was, as in Test 1, when the lubricant composition of the present invention was supplied, no seizure occurred on the high Cr cast steel roll. No scratches were observed on the product.

On the other hand, when the lubricant compositions of the comparative example and the conventional example were supplied, severe seizure and large abrasion occurred on the roll, and as a matter of course, scale flaws also occurred on the product.

(Test 3) During hot rolling of stainless steel (SUS304, SUS430, etc.) and carbon steel H-section steel in the section steel rolling line, the horizontal and vertical rolls of the finishing mill were tested as shown in Table 1.
Each lubricant composition shown in Table 2 and Table 2 was supplied by a water injection system using an oil supply device.
Similarly to the above, when the lubricant composition of the present invention was supplied, seizure did not occur on any of the rolls, wear was small, and no flaw was observed on the product.

On the other hand, when the lubricant compositions of the comparative example and the conventional example were supplied, intense seizure and large abrasion occurred in any of the rolls. The rolled product also had a number of severe flaws that required care for flaws with a coil grinder.

[0069]

As described above, when hot rolling is performed on steel using the lubricant composition of the present invention, seizure such as rolling of stainless steel or rolling under high load conditions is likely to occur. Even under rolling conditions, it has excellent effects on preventing seizure of steel materials on rolling rolls, drastically reducing wear on rolling rolls, and reducing frictional force during rolling. Generation of scale flaws in rolling can be prevented. As a result, the quality of the rolled product is improved, and the work efficiency is improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C10N 10:04 20:00 30:08 40:24

Claims (3)

(57) [Claims] 1. A lubricating base oil containing a metal salt phenate having a base number of 40 mg-KOH / g or more in an amount of 20 to 70% by weight based on the total weight of the composition. A lubricant composition for cold rolling. 2. A mixture of a metal salt phenate having a base number of 40 mg-KOH / g or more and a metal salt sulfonate having a base number of 40 mg-KOH / g or more is used in an amount of 20 to 70% by weight based on the total weight of the composition. A lubricant composition for hot rolling, characterized in that it is contained in a lubricating base oil in an amount. 3. The hot-rolling lubricant composition according to claim 1, further comprising a phosphonate in an amount of 5% by weight or less based on the total weight of the composition.